Cordless telephones have been in existence for some time. Cordless telephones operate utilizing a portable telephone unit in communication with a base station through a pair of RF transceivers in the portable unit and in the base station. When the device is operating, dial tone signals and voice signals are transmitted from the RF transmitter in the portable unit to the RF receiver in the base unit, and then over telephone lines in the ordinary manner. Signals received by the base station over the telephone lines are transmitted by the RF transmitter in the base unit to the RF receiver in the portable unit.
Cordless telephones are convenient in that they allow telephone communication without the burden of a cord. However, cordless telephones, like conventional corded telephones, currently require one hand to hold them in an operating position. Therefore, the user is freed from the cord but still must use one hand which otherwise could be used for operating a computer, filing, writing, household chores, sports activities or other activities. Finally, cordless telephones often suffer from poor reception, interference and poor transmitting quality as a result of poor signal to noise ratios in the RF transmissions between the portable unit and the base unit. This poor transmission quality is particularly detrimental when it is considered that the portable unit is intended for use in areas which could have high background noise such as, for example, out of doors, roadside backyards, busy kitchens where a meal is being prepared, laundry rooms where laundry machines are operating and warehouses and other industrial areas.
A device is needed that would include the convenient cordless feature of existing cordless telephones, but would also address the drawbacks of existing cordless telephones. It would be desirable for such a device to have good transmission quality, to shield at least some of the background noise, to be relatively lightweight and streamlined, and to be usable hands-free. Preferably, such a device would be snug-fitting, comfortable and light-weight and would not easily slip from the operating position while the user is moving about.
Other devices in the prior art have attempted to address some but not all of these problems with limited success. In U.S. Pat. No. 4,882,745 by Silver, a "cordless headset telephone" is described in which the portable unit is contained in an element that attaches to the user's head for hands-free operation. However, the Silver device includes only a single earphone to cover one ear while leaving the other ear open and does not have a means to increase the audio amplification over high background noise. This permits a high degree of interfering background noise which, as explained above, makes the device difficult to use out of doors and in other areas with high background noise. Also, the Silver device is held on the user's head with only a single headband. It has been found that this method of attachment may be insufficient to securely hold the complete portable unit, especially if the user moves about.
Another device is disclosed in U.S. Pat. No. 4,741,030 by Wilson. The Wilson device contemplates a corded or cordless headset with a dial board positioned near the microphone for easy viewing by the user. As in the Silver device, the Wilson device does not disclose the use of two earphones and a volume control to enhance sound quality and to block external noise. Another cordless telephone headset using only a single earphone is disclosed in U.S. Pat. No. 4,484,029 by Kenney.
Other devices exist for communication headsets, but they are not portable cordless telephones. Examples of such devices are in U.S. Pat. No. 4,782,527 by Williamson et. al, and U.S. Pat. No. 4,620,068 by Wieder.